"I cannot, in good conscience, allow our relationship to continue when events in Zimbabwe have been violating the central principles of the Sister Cities tradition," Mayor Mark Mallory wrote in a letter to Harare Mayor Emmanuel Chiroto.

Cincinnati has taken part in the sister city program for two decades and Harare has been a sister city for 18 years, The Cincinnati Enquirer reported Saturday.

Sister Cities International, a Washington-based non-profit group, refers to itself as a "global citizen diplomacy network" which began in 1956.

The group's executive director, Patrick Madden, said it is normal for a city to suspend a sister relationship to protest violence.

"I certainly understand and respect the mayor's position," Madden said